During the summer of 2015 in reaction to the questionable concept I continually heard about the American Chestnut (Castanea dentata) going extinct I decided to do a census of the American Chestnut on the Appalachian Trail from the Rausch Gap to the Lehigh Gap and other local trails. Over 38 days were spent on the census using a GPS equipped camera with many more days gathering data on American Chestnut reproduction and how the Chestnut Blight (Cryphonectria parasitica) affected the trees. A total of over 80 miles of Appalachian Trail was walked along with at least another 40 miles on other trails. More than 7500 trees of various sizes from seedlings to mature adults were found along two trail systems separated by about 25 miles. In three separate locations a total of forty-four trees were found bearing seeds. The limiting factor in American Chestnut reproduction was clearly shown to be access to direct sunlight, not disease. The obvious conclusion derived from this time in the field is that the American Chestnut is coming back without our interference. Attempts to hybridize it with non-native chestnut species to make “blight resistant” trees are unnecessary and is detrimental to the ecology of the Appalachian forest. This study will be continued in 2016 by walking additional trails.

1. 7500 American chestnut trees and
counting, the research that ate my
summer in 2015

2. NENHC 2016
April 2016

3. Richard Gardner
Heather Cuthbert
rtgardner3@yahoo.com
410.726.3045

4. A copy of this presentation along with other research
can be found at:
http://www.slideshare.net/rtgardner3

5. Abstract
During the summer of 2015 in reaction to the questionable concept I continually
heard about the American Chestnut (Castanea dentata) going extinct I decided to
do a census of the American Chestnut on the Appalachian Trail from the Rausch
Gap to the Lehigh Gap and other local trails. Over 38 days were spent on the
census using a GPS equipped camera with many more days gathering data on
American Chestnut reproduction and how the Chestnut Blight (Cryphonectria
parasitica) affected the trees. A total of over 80 miles of Appalachian Trail was
walked along with at least another 40 miles on other trails. More than 7500 trees
of various sizes from seedlings to mature adults were found along two trail
systems separated by about 25 miles. In three separate locations a total of forty-
four trees were found bearing seeds. The limiting factor in American Chestnut
reproduction was clearly shown to be access to direct sunlight, not disease. The
obvious conclusion derived from this time in the field is that the American
Chestnut is coming back without our interference. Attempts to hybridize it with
non-native chestnut species to make “blight resistant” trees are unnecessary and
is detrimental to the ecology of the Appalachian forest. This study will be
continued in 2016 by walking additional trails.

6. This study was conducted throughout the spring,
summer and fall of 2015 with additional data from
spring 2016.

7. The American Chestnut Federation: proudly
tinkering since 1989. Still clueless.
Me: walking for one year. Issue resolved.

8. The American Chestnut is not a problem to be
solved but rather a fascinating study in a human
mediated ecological disaster and the biological
response.

9. The ecological damage which the American
Chestnut Federation can cause is due to:
• a lack of study and understanding of the
Eastern Forests,
• inherently flawed paradigms about how natural
systems function and how human interference
can cause them to function “better” and
• the common human almost demonic drive to
tinker.

10. As an ecologist I continually see where
introductions of magic bullet plants to solve
non-existent ecological problems cause
problems: Sawtooth Oak, Russian/Autumn
Olive, Multiflora Rose, Chinese Lespedeza and
etcetera.

11. In Invasive Plant Ecology we have the Enemy
Release Hypothesis.
In part, this states that an overwhelming
number of native organisms cannot use
introduced non-native plants because they did
not coevolve together.

12. Hybridizing a native plant with another native or
especially a non-native creates a non-native
plant of little or no ecological utility.

13. Therefore, changing the gene structure of a
native plant by hybridizing with a non-native in
hopes of improving/saving the plant from
introduced diseases or pests is doomed to be an
ecological failure because few if any native
organisms using the native plant will be adapted
or adapt to use this hybrid due to changes in the
physical and chemical properties of the plant.

14. We do not want to do this in ecology because it
destroys the plant’s ecological utility as a food
source, etcetera.

15. Along with this my thinking is that native
organisms require high genetic heterogeneity
within the species utilized to match the variation
in native organisms utilizing them.

16. Limiting the phenotypic diversity by reducing
the sources of genetic material limits the
number of species and heterogeneous
individuals within those species which can utilize
a particular plant species.

17. And, it is hard to conceive how hybridizing one
plant with disease susceptibility with another
plant susceptible to the same disease makes a
disease resistant hybrid.

18. Simply put:
No matter how successful the hybridization appears
to be it is an ecological failure.
“The operation was a success, but the patient died.”

19. Cleora sublunaria on a mature C. dentata tree, April 19, 2016

20. It is better to patiently study the system to
understand what is happening and determine if
the apparent crisis is a real crisis.

21. If the crisis is real, then develop strategies which
have minimal or no ecological impact such as
looking for resisting/resistant plants.

22. In the case of the American Chestnut, the
answer was always there, but those with power
never looked for it.

23. 7,551* American Chestnuts total were found in the
spring, summer and fall 2015 on two sets of trails
separated by @ 25 miles at their closest.
*If there was 6” or 8 “ between stems in a cluster unless obviously a clone, the stems were counted as separate trees. This
is in line with the concept that animals such as squirrels and corvids made non-recovered caches of seeds which produced
multiple trunks in the same location.

24. 7,251 American Chestnut trees found on the
Appalachian Trail and related trails from Rausch Gap
to Lehigh Gap, @ 80 miles linear distance.
118 American Chestnut trees found on trails in the
Birdsboro Reservoirs area in a quick incomplete
survey to confirm data from the Hamburg Reservoir
area of the Appalachian Trail. (182 trees found at
French Creek, a related trail set, but unrelated study.)

25. Maryland Delaware
New Jersey
our home
Appalachian Trail study area
7,251 C. dentata trees
Downloaded from Google Maps 4/2/2016
Birdsboro and French Creek study area
300 C. dentata trees
25
miles
New York

26. www.google.com/maps
Mar. 9, 2016
Appalachian Trail on Blue Mountain
Birdsboro Reservoirs and French
Creek State Park
@ 25 miles between points
our home
Molasses Hill
Lake Ontelaunee
Middle Creek Wildlife Management Area
Mt. Penn
Expected locations of American Chestnut trees
Hamburg
Reservoir
Known groves of American Chestnut trees
Second and Sharps Mountains
Copied from Google Maps on Mar. 2, 2016
Topographical map showing distance between Blue Mountain and the Birdsboro Reservoirs/French Creek State Park with
other relevant information

27. Appalachian Trail
Rausch Gap
Lehigh Gap
Birdsboro Reservoirs and
French Creek State Park
Left to right, top: Dauphin, Schuylkill and Carbon counties; bottom: Lebanon, Berks and Lehigh
counties

28. Non-native Chestnut
Lehigh
Gap
Rausch
Gap
Blue Mountain: Rausch Gap to Lehigh Gap
2015 chestnut survey
Hamburg
Reservoir
Dan’s Pulpit
Allentown Shelter
Roundhead
yellow indicates C. dentata
groves
Lehigh
Valley
Nature
Center

29. One of the two most interesting discoveries is that the
Appalachian Trail is a refuge and a corridor for the
spread of the American Chestnut tree.

30. Other trails in Pennsylvania such as the Mason
Dixon, Conestoga, Mid State, Brandywine River,
Bartram and Laurel Highlands probably serve the
same purpose. I will exploring sections of these this
summer.

31. Another apparent correlation is that wider parts of
the AT and other trails serve as a corridor for the local
spread of the trees in that they provide an easy “low
friction” route for birds such as blue jays to fly along,
turkeys to run down and small mammals to use.
This needs more work as it was not an absolute
correlation, but an apparent one.

32. Extrapolating from a reference*, crows during the fall
migration may be spreading seeds along the ridgeline
the AT uses locally.
*American crow http://bna.birds.cornell.edu/bna/species/647/articles/migration
Fall migration

33. Over the length of the AT, the apparent southward
spread of seeds during the fall crow migration and
northward spread of pollen during the spring
pollinator migration are two of the most important
ways for the American Chestnut to maintain its
genetic heterogeneity. As part of this process disease
resistance genes spread between groves and widely
spaced trees.

34. Pollinators and crows – maintaining
genetic heterogeneity and spreading
disease resistance along Blue
Mountain
Pollinators move pollen north
during spring migration as the
trees bloom
Crows move seeds south
during fall migration
tree
nut

35. Within a set location, the seeds are spread by
rodents such as red squirrels, gray squirrels and
corvids such as blue jays.*
*Heinrich, B. 2014. American Chestnut Seed Dispersal and Regeneration. Northeastern Naturalist 21(4):619-628.
Heinrich, B. 2014. American Chestnut by Red Squirrels. Northeastern Naturalist 22(4):N19-N23.

36. tree
Seed spread by blue jays with red and gray squirrels
squirrels
blue jays

37. This is part of the process of basic Darwinian
evolution – the more resistant trees reproduce at a
higher rate because they are healthier than the less
resistant. (Eventually, the less resistant tree lineages
go extinct by continually losing the competition for
sunlight and other resources.)

38. Diseases and pests such as Bacterial Leaf Scorch
(Xylella fastidiosa), Emerald Ash Borer (Agrilus
planipennis), Gypsy Moth (Lymantria dispar dispar)
the Hemlock Wooly Adelgid (Adelges tsugae) and the
Elongate Hemlock Scale (Fiorinia externa) are opening
up the canopy.

39. Which means the American Chestnut may soon again
become the dominant tree in our eastern hardwood
forests as trees mature and reach the forest canopy.

40. Diagrams of how I think the American
Chestnut and how its genes are being
spread.
gypsy moth
larva

41. gypsy moth laying eggs

42. elongate
hemlock scale hemlock
wooly
adelgid

43. Trees

61. Seedlings

62. AT north of Auburn Overlook

63. tree from AT north of Auburn
Overlook transplanted at home

64. Sand Spring trail near Shartlesville

65. AT south of Lehigh Gap

66. Disease

67. The Chestnut blight was found in Brooklyn, NY in
1904. It spread to Pennsylvania a few years later.

68. When a tree becomes infected and a trunk dies it
fights back by coppicing, sending up new shoots from
the top of the root crown to produce multiple trunks.
(Multiple trunks appear to be a common growth habit
among some trees in our area such as silver maple.
This may be a common defense against disease and
other injuries.)

69. Castanea dentata

70. Acer saccharinum

71. One question which needs resolving is the
difference between multiple trunks from nut
caches vs. coppicing from disease. The following
two photos are most likely due to caching.

72. Castanea dentata

73. Quercus alba

74. Trees show lack of disease resistance in all age
classes and stem size.

80. Multiple areas of infection are common on
mature trees. Besides American Chestnuts this
pattern was found locally on oak, choke cherry,
birch and other species.

81. Disease on
American
chestnut. Castanea
dentata

82. Disease on
American chestnut
trees, Castanea
dentata

83. disease on red oak trees,
Quercus rubra

84. disease on black birch tree, Betula lenta

85. disease on choke cherry,
Prunus virginiana

86. disease on white birch, Betula papyrifera

87. disease on silver maple, Acer saccharinum

88. Flowers

89. The second important discovery this past summer is
that the limiting factor in tree reproductive success is
not the Chestnut Blight (Cryphonectria parasitica),
but rather access to direct sunlight on the apical ends
of branches.

90. All mature trees which received direct
sunlight had flowers, burrs and nuts.

91. Chestnut flowers are a good source of nectar and
pollen for insects such as bees at a time before many
non-tree flowers bloom. This gives pollinators early
season flowers to feed on as part of a continuous food
supply from mid-spring to frost.

105. Burrs and Nuts

106. Despite the blight, the trees are surviving to
reproduce.

107. • 46 trees have burrs in several distinct locations along
the areas of Blue Mountain surveyed.
• 40 of these trees are between Rt. 183 and Port Clinton
• 1 is on the Appalachian Trail on the top of the ridge at
the northern edge of the Hamburg reservoir watershed
@ 600 yards left of Gold Spring,
• 1 is on a trail near the Berks County highest point,
• 3 are near Round Head and the old AT and
• 1 is on the south side of the Lehigh Gap just north of
the AT.

108. Two trees near home which
produced burrs in 2015.
Left
Berks County, PA highest point
trail
lat. 40:31:15
long. -76:14:47
DBH:10.3”
Height: @34 feet
Right
Hamburg Reservoir, Appalachian
Trail in PA
lat. 40:36:20
long. -75:56 :51
DBH:7.0”
Height: @36 feet

109. 3 feet between
orange tape and
tree base, 6 feet
between green tape
and tree base
Location: Berks County, PA on the trail to the
highest point in Berks county, SGL80, lat. 40:31:15,
long. -76:14:49
DBH = 10.3”
Height: @ 34 feet

110. 3’ between green
and orange tapes x 2
= 6’ between green
tape and base of tree
Location: Hamburg Reservoir, Appalachian
Trail in PA, lat. 40:36:20, long. -75:56 :51
DBH = 7.0”
Height: @ 36 feet

111. Location: Berks County, PA, Rt. 183 north,
SGL110, lat. 40:32:22, long. -76:10:21
Chestnut cluster # 1, 3 trees, DBH L to R, 7
trunks total
Tree 1 = 4.8”, 3.0”
Tree 2 = 3.3”, 5.7”, 6.5”
Tree 3 = 5.3”, 5.9”
Height: tree 1 = @ 38 feet, other trees not
calculated

112. Location: Berks County, PA, Rt. 183 north, SGL110, lat.
40:32:21, long. 76:10:23
Chestnut cluster # 2, 2 trees, L to R
DBH
Tree 1 = 7.1”
Tree 2 = 7.3”
Height: @ 30 feet, 32 feet

113. Location: Berks County, PA, Rt. 183 north,
SGL110, lat. 40:32:21, long. 76:10:25
Chestnut cluster # 3
DBH = 6.2”
Height: @ 36 feet

114. 40 trees with burrs Rt. 183 north
to near Port Clinton
Port Clinton
Rt. 183

115. Burrs appear to open just after rain.

116. Rain swells the burrs causing them to open.

117. Burrs appear to open on both the tree and the
ground. Open burrs on trees can become food for
crows, blue jays and squirrels. On the ground they
can be food for mice, chipmunks, squirrels and
turkeys.

118. Wet soil makes it easier for corvids and rodents such
as squirrels to cache nuts in the ground which
enhances germination success.

119. Swelled burrs are soft from the absorbed moisture
which makes them a good food source for bacteria,
fungi, protists and insects – moist, nutritious, easy to
burrow in and easily digestible.

120. This allows the nutrients in the burr to be swiftly
recycled into the soil while creating a community of
organisms which benefit from the tree while giving
benefit to the tree.

121. Benefits to the tree may include increasing disease
resistance, lowering the load of pathogens and
predators near the tree, moving nutrients into the soil
close to the tree, etcetera.

134. Nut dispersal

141. Nuts in burrs had 3 basic shapes: spoon shaped
(spatulate), egg shaped (ovate) and house
shaped (truncate).
Most burrs had 3 nuts, often 1 ovate with 1
spatulate on both sides or a mixture of spatulate
and truncate shape.

142. wt. (g)
height
(cm)
width
(cm)
thickness
(cm)
3.7 2.2 2.0 1.4
Average dimensions of seeds dehisced on their own
wt. (g)
height
(cm)
width
(cm)
thickness
(cm)
3.5 2.1 1.8 1.5
Average dimensions of seeds manually dehisced
The following is measurements of the egg shaped
(ovate) seeds.
*No measurements were taken for the other shapes.

145. Path forward:
2016
1. finish survey in the Birdsboro/French Creek areas
2. extend the ends of the survey to the Susquehanna
River and the Delaware River
3. survey other relevant trails within 90 minutes of home
4. start looking at reservoirs to find fruiting trees as they
should have more open areas than trails
5. continue looking for seedlings in danger from trail
maintainers and hikers to transplant at home
6. continue collecting nuts to grow at home
7. identify and document pollinators and other
nectarivores on American chestnut flowers.

146. I plan to use a quadcopter (drone) with camera this
year to better understand and document what I see.

147. Our ultimate goal
To grow 2 successive generations (F2 generation) of
burr bearing American Chestnuts from seeds in our
yard.

148. Anyone who wants to join me is welcome to grab a
camera, their shoes, a day pack and do so.

149. Walk more
Tinker less

150. Richard Gardner
rtgardner3@yahoo.com
410.726.3045
http://www.slideshare.net/rtgardner3

151. Addendum

152. Miscellaneous thoughts on how American Chestnut
seeds are spread.

153. tree
physical factors – steepness of slope, texture of ground (smooth, rough,
boulders, duff, trail), proximity to and type of water way (ephemeral,
intermittent and perennial streams), wind, other trees, density and size
of understory plants
ephemeral/seasonal/intermittent stream
perennial stream
smooth trail
rough ground –
boulders and logs
trees and shrubs

154. tree
squirrels, chipmunks and other small mammals – distance nuts
are moved from tree depends on size of mammal, the larger the
mammal the further the nuts are moved
Small animals such as mice
Medium sized mammals such as squirrels
Larger mammals such as raccoons

155. tree
birds – distance nuts are moved
depends on size of bird, primary type
of movement, migration patterns, …
Crows depend on
whether migrating
or in home territory
Turkeys on trails and
through the woods,
primarily on foot
Blue jays through
the forest to
roosts and
perches

156. Non-native Chestnut